ChrisRX8PR

Hello guys,

Before anyone asks or says anything I'd like to state 2 things:

1. I probably had about 20 different questions when I decided to do the swap and for the last couple months I have done nothing but search and read which answered about 85% of the questions I had...if I am asking this here is because I did not find a suitable answer to my question.

2. Dowel pinning and studding is a prefference thing in my opinion unless you are really pushing the limits of the engine, I personally have done (myself, on 13b's) and like dowel pinning, I am just saying this so that this doesn't turn into a dowels vs studding thread.

Now to my question:

After finally breaking my goals of 500whp on a renesis engine I have made the decision of doing a 20b swap. I have the technical knowledge and the fabrication skills/experience, that is not the problem. My question has to do specifically with the 20b. I know for a fact that 350-400whp on a 13b is no issue without dowel pinning, this is 175-200whp per rotor. My build is for reliability, I was happy with 500whp on the renesis and I want about the same power level but more reliably so I am throwing a 20b in there with a GT4202 and plan to not get above 12psi (about 550whp from what I have seen on the forum). That is less than 200whp per rotor. I want to know if dowel pinning is necessary for that power level on a 20b that will only be driven on street tires....at most with some toyo r888's. It will probably go to the strip once or twice a year if that, the rest of the time it will be driven from a roll mostly. I am worried about engine flexing due to the assembly being so long compared to the 13b. Should I be looking into dowel pinning the engine?

Thanks in advance to everyone.

Chris

turbotommy

iTrader: (3)

It probably will depend on what series motor 20b you have. the C and D series have thicker irons in the dowel pin area... my friend has a B series motor ( irons are not as thick ) and he makes 525 rwhp at 12psi on a gt42 with no dowel pinning or studding... his car runs beautiful..no issues
From my experience i dont think its going to be necessary at the level you plan on running your car at. The reason i say that is because with my personal experience with my 20b D series motor, i made 740rwhp and havent had any issues. i have no dowel pinning or studding of any sort. hope this helps. .... it is a start at least. goodluck with your beast

Tom

ChrisRX8PR

Wow....talk about a concise answer with no BS...Thanks man.

So I guess I have to make sure I get a D or D series motor then. I have not made the purchase, I have been working on tearing down the current setup and the cross member extension etc. How do I determine if its A, B, C or D? Is this engraved somewhere on the engine exterior where it is easily visible? I would like to have the people I am buying my engine from read the numbers for me before I pull the trigger...boy am I happy I started this thread...

Thanks

Anyone else with experience in this dept.?

Chris

diabolical1

iTrader: (3)

no 20B experience here. give THIS a gander though. Patman shares his thoughts on the subject.

you can check with the users Japan2LA (he sells them) and RotaryBoyz (i think he has a C-series for sale) for the engine itself. i'm sure there are other trustworthy sources, but those are the two that came to mind first.

ChrisRX8PR

Thanks!

Anyone know how to read the letter Code on a 20B?

Chris

calculon

iTrader: (29)

I promise that Japan2LA does. It is stamped into each iron, on the top right portion as viewed from the front of the engine.

Banzai-Racing

iTrader: (11)

It is stamped on every iron and housing

hwnd

iTrader: (4)

I'm not 100% sold on this "series" bullshit where a D series is able to produce 9 trillion lbs of torque and an A series is only able to produce 6 billion.

Mr. Lopez has built many go-fast 20B's and gave me his thoughts on the subject which ended up being "series doesn't matter". So while there may be more material on the 20B later series - I dont think that is the secret or anything to do with TQ or HP directly.

I will say that if you had a bad tune then I can see how more material would help to prevent cracking t an earlier point. but i surely wouldn't hold out for "D" only. Just doesn't make any sense to me given the wealth of information here on the internets.

ChrisRX8PR

I see...but that is precisely what I was concerned. I would like a safety factor in my engine as high as possible for my power goals. Maximum power aside...at a given hp level, if it detonates a C or D series motor would have a better chance of not suffering damage to the dowel pin lands, right? That is what I am looking for, just an extra cushion of safety that allows me to not have to dowel pin the engine since my power level goals are pretty conservative.

Chris

calculon

iTrader: (29)

I think that almost everybody will agree that the answer to this question is "that's right."

I don't think that hwnd's statement should be given that little attention though. In most cases, detonation is completely preventable (especially at the power levels you're looking for), and it therefore should be. If you blow a seal, which has nothing to do with landing thickness, you're still running a risk of ruining those irons.

hwnd

iTrader: (4)

well not exactly, you'll still have seals to break first.

I just got off the phone with Racing Beat, I asked these questions:

Q: with a 20B PP (n/a), would "series" matter in terms of cracking?
- would i opt to buy a later-series 20B vs. an older series 20B?

A: No, thats nonsense unless you plan to turbo. But even then, you probably wont break the motor because of tuning issues (unless its really bad). Autocross racers dont complain too often about breaking the irons but those few who do use pretty harsh pressure plates.

Q: Assume I do turbo a early series 20B and my computer-tune is safe / under powered, would i stand a chance of breaking it then?

A: Again, if you're drag racing - probably. This really depends on your tune (but something else will break first before breaking the rear iron). Also if you drag-race the car and use a heavy pressure plate and slam the clutch down during shifts, yeah that might break the rear iron.



So I did probe a little further and asked about wild setups like 1000hp+ etc etc and his advice was "tune" & said "the material thickness differences aren't enough to keep the engine from breaking - what will break the early series will probably break the newer series." - this is what i've been told by some of the bigger fish in our pond (again and again).

in fact, one big fish (often seen with 4rotor setups) said "i've been doing 20b builds long before the public even know about them - `series` my ***! doesn't matter". Again, buy the latest and greatest but I'm still not believing the bullshit about "ohh noooeeeee your 20b haz weak spots!! nooooesss!!!".

then again, it also works well to drive up the prices on those C's & D's...doesn't it? :-)

Japan2LA

iTrader: (256)

Nonsense...
Late B code.. (800 or so and up) and C and D codes are the better engines plain and simple...

its Been argued over and over again..

The early Pre A code, A code, and B codes break in the same spot on the Thick center plate..

Break on low boost
Break on the strip
Break on the dyno
etc etc etc..

I have talked to Abel about this many times..

Thicker dowel pin land plates are better

Mazda redesidned for a reason..


The great equalizer.. 12.7mm Studkit!

ChrisRX8PR

Ok....so if I can I should get a C or D motor, right? Now I have to find out who of the sellers importing JDM engines has one so I can rebuild it, port it, replace apex seals and throw it in the car.

Chris

turbotommy

iTrader: (3)

c or d is ideall ( like a 3rd gen motor )

a or b....( like a t2 motor )

what happens to an unpinned t2 motor at high boost??.........cracked iron at dowel area with oil all the way down the track..... lol Either pin it....or get a C or D series. I know a D series will hold up to 740rwhp unpinned because ive done it..... 741rwhp???? well....i dont know yet lol

hwnd

iTrader: (4)

Define "high boost" - 20psi? 60psi?
There are so many factors in here and the engine tune is a good deal of those factors. Please be more specific.

I dont honestly think anyone here has the technical background to prove any of the reason WHY these engines break when variables like condition, engine tune, etc are removed from the equation. Seems like a group of people chiming in with "I heard" or "so and so told me this and that". It isn't fair to compare a T-II engine with a 20B engine. On a tune thats 80% competent, 20PSi is a big difference for both motors.

Let's get some prove that the thickness-difference really makes a difference.

How much force can the difference between the early & late series actually make? I'm sure there are vendors here with both engines that could very well measure the thickness of both early and late. i dont think the difference will make two squirts of **** at 30psi.

It'll be a long, cold day before we'll have a laboratory to actually test these cases. Until then, I guess the best you can do is go based on word of mouth - not me however.

patman

iTrader: (3)

In my experience, temperature has more to do with it than anything- with one exception (broken motor mount caused the iron to go) every time I've broken an iron it has been when I was putting a lot of power down (IE 5th gear WOT) AND the engine temp was higher than it should have been. I have detonated the crap out of a high power engine before and not had any issues with the irons. Detonation destroys seals, high temperature and torque destroys irons.

My advice to the OP is to get a good tune and a good water AND OIL cooling system, and not worry about pinning for 500whp.

I would rather have a later series engine not only for the irons, but for the (allegedly) stronger e-shaft as well. That said, I have an A series because while I think the later ones are neat, I'm poor and I wasn't about to pay 1500 extra clams for one. For (less than) that much extra cash, you could have the engine studded, and then the issue would be moot.

hwnd

iTrader: (4)

well said..

diabolical1

iTrader: (3)

from the volumes upon volumes that i've read on the subject, this is what makes the most sense to me.

to me, this argument is in the same vein as the "2 mm vs. 3 mm seals"-argument. it's definitely the same as the whole "S4 13B-T vs. S5+ 13B-T"-argument. i've always maintained the mindset that without the right support (hardware, tuning or both) for the engine at the power levels one tries to achieve, you're likely to blow any one of them up. there's no arguing structural enhancements, but as for how much that enchancement lends to bulletproofing an engine, i think if real, objective tests were performed, many people might be surprised that it's not as much as they think.

calculon

iTrader: (29)

FWIW, here's mine. No impressions on the rotor housings, just the irons.
Front:

Thick:

Thin intermediate:

Rear:

hwnd

iTrader: (4)

I've still got an A out in the garage - I'll measure that tonight and provide photos.

Japan2LA

iTrader: (256)

Look at the pics

Front plate from Pre A code engine # 391
thickness of the dowel pin land : 7.9248mm

Rear plate Non-stamped D code engine
Thicknes of the dowel pin land : 12.065mm

BIG difference!!

Over 4mm Thicker!!

This is why the C and D code Engine Blocks are Stronger

Hard to argue with the sideplates being 4mm thicker on the dowel pin lands..

hwnd

iTrader: (4)

4.1402mm difference

so it's 1/3rd thicker roughly... which means it takes 2/3rds the power to break of a later series...
is that what you're saying?

so where is the limit you're implying? at what power level? Tommy did 700+ hp so our non "C" & "D" are only good for 2/3rds the power?

this is bogus.. enjoy the extra 4.1402mm

Japan2LA

iTrader: (256)

I have a customer who has cracked/broken the thick center iron TWICE on a small dowel pin land motor at 15psi @ about 550hp.

They are weaker blocks

The fix: Small dowel pin land motor and a guru studkit and you will not break a sideplate ever again..

In my build I am not even willing to gamble with my D code block... Already fully machined to accept all 18 12.7mm studs

zayrx7

If you dowel pin make sure you get someone, who can do it right. I have seen a # of motor dowel pin and they have taken out to much material.

jamespond24

iTrader: (13)

I would stick with a C or D code just for safety and $$$. I have never broken the rear iron on a FD but broken more than 5 on the T2. Tunning is everything but sometime they're not there at your convience.